Some players might be wondering if Pokemon Go applies a long-term reward system that grants players bonuses for achieving a particular milestone. However, as time passes, it has been confirmed that Niantic has not yet integrated anything in terms of long-term rewards. Apparently, several trainers are putting up some ideas for the future update and that includes the Golden Egg reward.
As seen on the popular anime website Otakukart, they came up with an idea of rewarding players for hatching eggs in Pokemon Go. They stated about a reward item called Golden Egg. This item would be awarded to players for hatching 500 Pokemon Eggs. On the other hand, the Golden Egg's KM requirement would settle between 12 and 15 KM in order to separate it from other Pokemon Eggs.
Based on the report from Frag Hero, there are three ideas proposed on how this Golden Egg works. First is when the egg hatches, players can choose a non-legendary Pokemon with an instant CP of 1500 that has preferable IV stats. This would help trainers to have the freedom to choose their preferred Pokemon or also filling up their PokeDex with a special Pokemon such as region-locked.
Another idea proposed is to award players with EXP, Incense and Lures. As reported, players could get a 10000 EXP, 5 Incense and 5 Lures. Upon adding this, the trainer will be able to pick one out of each biomes which will narrow down their hunt into a particular Pokemon in the egg.
Lastly, whenever trainers successfully hatch their respective Golden Eggs, they will be given an opportunity to fully relive any event they have missed. For instance, if one player has missed one public event either Halloween or Christmas, he or she will be given a chance to fully relive his or her chosen event and benefit from it with a similar time duration.